Not really sure what you want to achieve from your description but, if you want a custom post type in the loop, do this:

// Add the 'your_post_type' postype to the loop.
add_action('pre_get_posts', function(WP_Query $query){
if(is_admin() or is_preview()){
return;
}
// Only add them to the loop on Home/Front-Page
if((is_home() or is_front_page()) and empty($query->query_vars['suppress_filters']){
// This has to be an array so fix it if required
$post_types = $query->get('post_type');
if(empty($post_types)) $post_types = array('post');
elseif(is_string($post_types)) $post_types = array($post_types);
// Add one or more CPT-s to the loop here (merge old with new)
$query->set('post_type', array_merge($post_types, array(
'your_post_type',
// 'another_post_type',
// 'maybe_another_post_type',
)));
}
return;
});

Custom post types require a bit more manual tuning when you use them. Not only do you need to enable them but also list them or add them to the loop, create an archive (or at least link to it).